<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>圆弧转动</title>
</head>
<link rel="stylesheet" href="../common.css">
<style>
  :root {
    --color: orange;
    --lineColor: rgba(102, 163, 224, .2);
  }

  body {
    background: #222;
    overflow: hidden;
  }

  section {
    position: relative;
    width: 200px;
    height: 200px;
  }

  section::before {
    content: '';
    position: absolute;
    height: 10px;
    width: 10px;
    border-radius: 100%;
    border-top: 1px solid orange;
    top: 50%;
    left: 50%;
    margin-top: -5px;
    margin-left: -5px;
    animation: turn 1s infinite linear;
    filter:
      drop-shadow(0 0 2px var(--color)) drop-shadow(0 0 5px var(--color)) drop-shadow(0 0 10px var(--color)) drop-shadow(0 0 20px var(--color));
  }

  .box,
  .box::after,
  .box::before {
    border: 2px solid var(--lineColor);
    border-left: 2px solid var(--color);
    border-right: 2px solid var(--color);
    border-radius: 50%;
  }

  .box::after,
  .box::before {
    position: absolute;
    content: '';
    left: 50%;
    top: 50%;
  }

  .box {
    width: 200px;
    height: 200px;
    position: relative;
    animation: turn 1s linear infinite;
    transform-origin: 50% 50%;
  }

  .box::before {
    width: 180px;
    height: 180px;
    margin-top: -90px;
    margin-left: -90px;
    animation: turn2 1.25s linear infinite;
  }

  .box::after {
    width: 160px;
    height: 160px;
    margin-top: -80px;
    margin-left: -80px;
    animation: turn 1.5s linear infinite;
  }

  .box-circle,
  .box-circle1,
  .box-circle2 {
    border: 2px solid var(--color);
    opacity: .9;
    border-radius: 50%;
    position: absolute;
    left: 50%;
    top: 50%;
    transform-origin: 50% 50%;
    transform: translate(-50%, -50%);
    width: 100px;
    height: 100px;
    animation: rotate 3s linear infinite;
  }

  .box-circle {
    animation-delay: 0.2s;
  }

  .box-circle1 {
    animation-delay: 1.2s;
  }

  .box-circle2 {
    animation-delay: 2.2s;
  }

  @keyframes turn {
    100% {
      transform: rotateZ(-1turn);
    }
  }

  @keyframes turn2 {
    100% {
      transform: rotateZ(1turn);
    }
  }

  @keyframes rotate {
    100% {
      border: none;
      border-top: 2px solid var(--color);
      border-bottom: 2px solid var(--color);
      transform: translate(-50%, -50%) rotate3d(.5, 0.5, 0.5, -720deg);
    }
  }
</style>

<body>
  <section>
    <!-- <div class="box"></div> -->
    <div class="box-circle"></div>
    <!-- <div class="box-circle1"></div> -->
    <!-- <div class="box-circle2"></div> -->
  </section>
</body>

</html>